The present invention relates to the electronics programming arts. It finds particular application in conjunction with configuring integrated circuit (“IC”) devices used as controlling devices and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to configuring other types of IC devices.
An IC controlling device (e.g., a microprocessor device (a central processing unit (“CPU”)) and/or an Application Specific Integrated Circuit (“ASIC”)) requires an internal configuration to be loaded from an external source upon being reset (e.g., when power is applied). A conventional approach for providing configuration data to the controlling device involves the use of a plurality of configuration pins on the controlling device. The logical signals communicated to the various configuration pins are static. In other words, once the configuration pins are set to either a logical high or low, the logical states of the configuration pins do not change and, furthermore, the controlling device is configured.
One drawback to this conventional approach for configuring a controlling device is that because the configuration pins are hardwired, the logical signals transmitted to the respective configuration pins are static. Therefore, the number of possible configurations for the controlling device is proportional to the number of configuration pins. As such, the flexibility of the controlling device is limited. At the same time, the cost of manufacturing the controlling device is proportional to the number of pins. Consequently, conventional controlling devices that include several configuration options must include a proportional number of configuration pins and, furthermore, are relatively expensive.
Another conventional approach for providing configuration data to the controlling device involves the use of a previously configured electrically erasable programmable read only memory (EEPROM) or other data source, which is hard-wired to the controlling device. More specifically, a plurality of pins (e.g., four (4)) on the EEPROM are hard-wired to a plurality (e.g., four (4)) of configuration pins on the controlling device. Upon power-up (reset), the controlling device reads the contents (configuration data) of the EEPROM via the configuration pins.
The controlling device is typically configured by transmitting respective “high” and “low” logical signals (configuration data) from the pins on the EEPROM to the plurality of configuration pins on the controlling device. The logical signals communicated to the various configuration pins are used only for configuring that device. Configuration of a second controlling device requires a second configuration data source and has associated corresponding costs.
The present invention provides a new and useful method and system of configuring IC controlling devices that addresses the above problems.